The present invention relates to a refuge device from a high place (a portable refuge tool), by which a person who has any body weight such as a child and an adult may descend from the high place to the ground substantially at a constant velocity at all the time in the case where he or she takes refuge from the high place and so on.
There has been conventionally provided a portable refuge tool that may descend to the ground at a constant velocity from a high place of a building in case of emergency such as fire.
However, in the conventional refuge tool, there is an allowance range for the load, and the refuge tool is used in accordance with the weight of the person who uses the tool.
For instance, a refuge tool used by a person having a body weight of 40 kg and a refuge tool used by a person having a body weight of 80 kg are different from each other. If the refuge tool to be used for the person having the body weight of 40 kg is used for the person having the body weight of 80 kg, then the refuge tool does not work as the refuge tool, which is very dangerous.
Accordingly, this type refuge tools should be prepared for various persons who are to use them. For instance, in hotels or Japanese style ryokan (hotels), a variety of refuge tools should be prepared in conformity with various allowance body weights while estimating the body weights of the persons who are to use the tools. This is very inconvenient.
Therefore, as a result of the long term studies, the present inventor had invented a portable refuge tool that could descend substantially at a constant velocity even if the refuge tool was used to a person having any body weight (JPB Hei 3-62114).
The present invention is a further improvement to the above-described invention as a base. More specifically, in an arrangement in which a plurality of static plates (brake plates) rotating in oil are provided on a rotary shaft provided with a pulley whose winding diameter is varied in response to the body weight (load), the outer shape of this rotary shaft is formed into a rotation preventing shape in order to enhance the mass productivity with an easy manufacturing and assembling property without increasing the cost. At the same time, modified holes that may fit and retain in conformity with this outer shape is provided in the static plates or a pulley forming plate. As a result, simply by fitting and retaining the modified holes to the rotary shaft, it is possible to couple the pulley (static plates) with the rotary shaft to be rotated together. In addition, even if a rope is loosened in the initial stage upon the descending and the rope has the minimum winding diameter abruptly by the change of the pulley groove so that the rope is brought into the outer circumferential surface of the rotary shaft, the outer shape of the rotary shaft is not formed simply into a rectangular shape or a hexagonal shape in cross section in order not to generate any cutting force locally in the rope neither simply into a key shape to provide a novel refuge tool from a high place in which a number of convex and concave stripes are formed in concave and convex outer circumferential surface continuously in the circumferential direction.
The summary of the invention will now be described.
According to the present invention, there is provided a refuge device from a high place in which a rotary shaft is provided rotatably within a casing provided with a rope winding portion around which a rope is wound feedably, a pulley for winding the rope to be fed is provided on the rotary shaft, static plates rotating within a closed chamber filled with oil and generating a brake force are provided on the rotary shaft, an interval of a pulley groove of the pulley is varied in response to a load to adjust the winding diameter, and a rope feeding brake mechanism for controlling so that the rope feeding velocity is kept substantially at the constant velocity irrespective of the magnitude of the load is provided, characterized in that an outer circumferential surface of the rotary shaft on which the pulley is provided and with which the rope is brought into contact while the winding diameter is at minimum upon the application of a large load is formed into a concave and convex outer circumferential surface formed by a number of circumferentially juxtaposed concave and convex stripes having a length in an axial direction and a modified hole identified with the concave and convex outer circumferential surface is fitted and retained to the rotary shaft whereby pulley forming plates of the pulley are coupled in a rotation preventing manner but slidably to the rotary shaft.
Also, according to the present invention, there is provided the refuge device from a high place according to the first aspect of the invention, wherein apex portions of convex portions forming the concave and convex outer circumferential surface is rounded and chamfered and formed into the concave and convex outer circumferential surface concave and convex continuously in a wavy form in the circumferential direction, whereby when the rope is brought into contact with the concave and convex outer circumferential surface of the rotary shaft upon the application of a large load, a local cutting force is hardly generated in the rope.
The best mode of the present invention (how to embody the invention) will briefly be described with resultant effects.
For instance, after the rope wound around the rope winding portion provided in the casing is wound around the pulley of the rotary shaft provided within the casing, the rope is fed out to the outside of the casing, the fed-out end is fixed to, for example, the building side, the casing is mounted through a mounting portion on the person who takes refuge from the high place, when the person descend from the high place, the rope fed while rotating drum is fed out to the outside of the casing while rotating the rotary shaft through the pulley for descending, at this time, the plurality of static plates are provided on the rotary shaft, the static plates generate the rotational resistance (brake force) for rotation within the closed chamber filled with the oil, and also, the pulley groove is varied in response to the load, the winding diameter is varied to the rotary shaft of the rope so that the rope is fed substantially the same velocity irrespective of the magnitude to the load (body weight) and the person may descend substantially at the same velocity.
The theory why the descending velocity is kept substantially constant is described in JPB Hei 3-62114 and accordingly the detailed explanation therefor will be omitted.
Furthermore, according to the present invention, the outer shape of the rotary shaft is formed into the rotation preventing shape. At the same time, the modified hole that is identified with the outer shape and fitted and retained is formed in the pulley forming plates (static plates) of the pulley. Only and simply by fitting and retaining the modified hole to the rotary shaft, the pulley (static plates) may be coupled to be rotated together with the rotary shaft. In particular, the pulley forming plates are slidably coupled to the rotary shaft in a rotation preventing manner so that the pulley groove may be varied in response to the load. Accordingly, it is easy to manufacture and to facilitate the device without increasing the cost, which enhance the mass productivity.
Furthermore, since the outer shape of the rotary shaft is not simply into the rectangular shape or the hexagonal shape in cross section or the key shape is not formed into a single shape but the outer shape is formed into the concave and convex outer circumferential surface by a number of concave and convex stripes having a length in the axial direction that are continuous in the circumferential direction, even if the rope is loosened in the initial stage upon descending and the rope has the minimum winding diameter at once due to the change of the pulley groove so that the rope is brought into contact with the rotary shaft outer surface (concave and convex outer circumferential surface), the rope is hardly brought into pressing contact only with one corner edge and is likely to slip because of a number of concave and convex portions. Accordingly, since the local cutting force is hardly generated in the rope, the safety aspect is enhanced to thereby provide a novel refuge device from a high place which is extremely superior in practical use.